Supporting Model And Scheme Optimization Of Construction Foundation Pit In Tianjin Area

The geological and hydrology conditions of Tianjin has been expounded in the paper, offered the geography, topography, terrain, detailed stratigraphic sequence chronology of Tianjin area in detail and made a division of stratum, introduced the origin, age, diffences of the stratum which would influence construction projects, following ,the paper given out the division figure of stratum in Tianjin area and detaild analysed the engineering geological conditions in different ages, different regions, different causes of stratum, through the treatment and analyzed of the Survey data, the basic physical and mechanical index of stratum in urban areas and the coastal belt has been give out. Meanwhile hydrological and geological conditions like the ancient water system and ancient billabong which would influence the construction of project has also made detailed presentations, the water table and the ground water corrosion which would influse the engineering has been made simple analysis.Secondly, many data of construction foundation pits has been collected in the Tianjin including support mode data, but also the stratum, water table of the construction site, this were summed up, and made the papers rich on the geological conditions in Tianjin, through analysis and summariz of data about the foundation pits in Tianjin, obtained empirical supporting mode of foundation pit on the 6 m, 6-10m, 10-15m, more than 15 m in Tianjin. Following, made the analysis of various indicators which influce the supporting mode, then, selected out the important indicators, in the end, show the optimization reference table of supporting plans design about foundation pit in Tianjin.Through the reference tables, we can make the adoption of whole supporting mode about the foundation pit.Through the analyse of supporting mode about the foundation pit in Tianjin, obtain that one of mostly supporting method is pile and anchor, thus the various factors which influence the pile and anchor were analysed in the paper. the pile supporting include: Support pile containing solid depth, fulcrum position , the moment, the pile diameter and piles margins distance; anchor supporting structure: layers of anchors, anchor spacing, anchor of the angle, length, diameter, etc.. Based on the effects degree on supporting structure we can make generalized and selective preference about the above factors, then draw out parameter which required by optimization mode, such as pile diameter, piles margins distance, and support pile containing solid depth ,further, through the use of genetic algorithms found model for supporting structure. Finally, the model was found successfully, through the use of genetic algorithm model calculation and analysis, a supporting plan of a deep pit in coastal of Tianjin were obtained, at the same time, internal force distribution of supporting structure were come true through use of Matlab program. Then, using software of Lizhen and Qimingxing of Tongji University for the deep excavation supporting designing, and make compare for three supporting programme through analysis of the results, made the conclusion that genetic algorithm selective preference modle used in the pit supporting designing is economical and specific ideals.